Megakaryocytosis in transgenic mice. Four-micron formalin-fixed sections from AM107 (A, C, E, and F ) and control (B and D) tissues were stained with hematoxylin and eosin and photographed at 400× magnification. (A, B) Bone marrow; (C, D) spleen; (E) liver; (F ) lung. Representative megakaryocytes (megakaryocyte nucleus in lung) are indicated by arrowheads. Bar = 22 μm.